This project will investigate: 1) using radioactive metabolic precursors, whether 99mTechnetium (99mTc) and 111Indium (111In)-labeled leukocytes are biochemically inhibited when studying the following cells functions: a) DNA, RNA, and protein synthesis; b) reproductive ability; c) response to mitogens, PHA, conA, LPS; d) ability of the radionuclide-labeled immune leukocytes to act as cytotoxic cells against 51Chromium-labeled tumor cells. 2) Using 99mTc or 111In-labeled Murine (Moloney) Sarcoma Virus (MSV) tumor cell immunized C57B1/6 mouse spleen leukocytes, we will study the in vivo MSV tumor site accumulation of these cells using gamma camera imaging and quantitation by sacrifice of the animals and measurement of individual organ tissue and tumor reactivity. Aspects to be studied: 1) In vivo tumor accumulation of the radionuclides only. 2) In vivo tumor accumulation of MSV-immunized and non-immunized radionuclide labeled spleen leukocytes. 3) The specificity of the in vivo tumor accumulation of the MSV cell immunized radiolabeled spleen leukocytes to only a MSV tumor site.